The invention is directed to a method for monitoring the earth's surface using synthetic aparture radar.
Monitoring of the surface of the earth is required for many applications. A moving aircraft, e.g. an airplane or a dirigible or a satellite, may be used, if the monitoring for the most part must be independent of the influence of weather conditions, e.g. clouds and/or fog, it makes sense to provide an aircraft with a radar sensor having a viewing direction toward the earth's surface. In the event that high spatial resolution must be achieved during the monitoring, it makes sense to use a radar sensor with a synthetic aperture. This radar sensor is operated, for example, in the so-called SAR mode or the DBS mode (operating mode). This type of radar monitoring requires that the flight parameters in particular are always known, e.g. flight elevation, flight path, and flight speed of the aircraft. Only if these are known can radar images, recorded successively in time with the synthetic aperture method, be evaluated with predetermined accuracy, without the occurrence of errors and/or interferences such as fuzzy images. The aforementioned flight parameters can be determined, for example, with an INS (inertial navigation system).
Such a method has the disadvantage of being technically involved and not cost-effective because an autonomous device, the INS device, must be used to determine the parameters, required in particular for SAR radar images.